Direct access storage devices (DASD) have become part of every day life, and as such, expectations and demands continually increase for greater speed for manipulating data and for holding larger amounts of data. To meet these demands for increased performance, the mechanical assembly in a DASD device, specifically the Hard Disk Drive (HDD) has undergone many changes.
In operation, the hard disk is rotated at a set speed via a spindle motor assembly having a central drive hub. Additionally, there are tracks spaced at known intervals across the disk. When a request for a read of a specific portion or track is received, the hard disk aligns the head, via the arm, over the specific track location and the head reads the information from the disk. In the same manner, when a request for a write of a specific portion or track is received, the hard disk aligns the head, via the arm, over the specific track location and the head writes the information to the disk.
An important function in an HDD is seek control. Seek control means moving a head from one track to another. It is desirable to move this head very quickly in order that reading and writing may be performed more quickly. However, the actuator vibrates if the head moves too fast, causing settling difficulty due to these vibrations. Additionally, even though fewer vibrations occur when the head moves slowly, the seek trajectory also becomes slower resulting in performance degradation. For example, a slower seek trajectory results in slower read/writes. Consequently, there is a need for a system and method which provides for a smoother actuator movement while experiencing a rapid trajectory.